Ductwork, or lead-ins, are particularly used onboard ships where a pipe is to pass through the partitioning from one compartment to the next compartment. The partitioning can both be the vertically oriented walls separating individual compartments on a deck and the horizontally oriented partitionings separating individual decks.
Ductwork made of metal may e.g. be fastened to the partitioning by welding, on the condition that both parts are made of a weldable metal. This technology has been used for many years as the ductwork can be established from one side. This is an essential advantage, particularly by ductwork between partitionings between decks as it is not required with a fitter at each side of the partitioning. However, mounting by welding implies several disadvantages where the most important is the fire hazard. It is not an infrequent incident that a great number of larger or smaller fires occur during the construction of ships with ductworks, as sparks from the welding may easily ignite e.g. packing, auxiliary materials and equipment in the vicinity of the mounting site.
DE 20 2005 007 846 U1 describes a ductwork for leading a pipe through a boring in a partitioning. The ductwork includes a flange bearing against a partitioning, a clamping means with a fixing device and a bolt with a nut. The bolt bears against one side of the flange. It has been passed through an opening in the flange, an opening in the clamping means and an opening in the fixing device. The nut is screwed on the bolt and bears against the fixing device. The fixing device is a rod which is inclining abutment against the clamping means which bears against the flange. By rotating the nut on the bolt, the fixing device is brought into a more upright position. Hereby is achieved engagement with the internal side of the boring as the fixing device reaches a greater diameter. The single ductwork in DE 20 2005 007 846 U1 only fits borings with limited diameter range as the widening of the diameter of the fixing devices is limited. Moreover, the flange cannot be mounted from one side of the partitioning. It is necessary to have access to both sides.